Time machine works almost perfect. Time machine is a backup application built into MAC OS 10.5. I have it set up with an apple time capsule (1TB) and I have on two or three occasions permanently deleted receipts (on accident) from NWorks. When this has occured I just open up time machine and go to the previous Neat Library and restore. It works great.
Of course there is always a BUT. Time machine makes a complete backup of your Neat Library in my case it has grown to 1.4 GB. Each time I've restored the library it takes a long time. Also anytime I make a change to the neat library Time machine grabs the entire 1.4 GB. So if I just add 1 receipt it triggers time machine to copy that whole 1.4 GB. Not a big deal but it waste space and makes backups take a long time. I have the impression that applications on OS X can be written so that time machine only grabs the changes within the file. For example iPhoto and itunes. My iphoto and itunes libraries are huge, but if I make 1 change in itunes or add only 1 photo to iphoto time machine only grabs the changes within the iphoto and itunes databases. I would hope that one day Neat Co would make NWorks for Mac set up with the same logic. It would free up some space on my time capsule